1. Field of the Invention
The present invention relates to tools for adjusting the position of side quills on a differential.
2. Description of the Related Art
In a conventional differential assembly, bearings, typically roller bearings, are provided to support the differential housing on the wheel drive shafts. Adjustable side quills are provided to pre-load the bearings. These side quills usually are threaded into the differential housing, so they can be screwed in and out of the assembly by rotating the quill. The quills normally are coaxial, so that screwing the guills closer together increases the pre-loading on the bearings, while unscrewing the quills so that they are farther apart reduces the bearing pre-load.
In addition to adjusting the bearing pre-load, such side quills can be used to adjust the backlash between the differential ring gear and the drive shaft pinion gear. To do this, the relative spacing between the side quills is kept constant, but the side quills are screwed in and out of the differential housing by the same amount in the same directions. This shifts the differential ring gear to one side or the other of the housing, which in turn has the effect of adjusting the backlash spacing between the ring gear and the pinion gear.
The adjustable side quills typically have crenellations on their outer edges to aid in adjustment. Conventionally, they are adjusted to positioning a screwdriver, punch or similar tool to engage the crenellations, and then rotating the quills to move them in or out of the differential assembly. Normally, the two quills first are moved relative to one another until they are positioned to provide the proper pre-loading on the bearings. Next, the operator shifts one quill by a certain amount, and then the other quill by the same amount, to shift the entire differential assembly to adjust the backlash. Once the final positioning is obtained, a roll pin is inserted to engage the crenellations in each quill and hold them stationary relative to the housing.
This technique has several disadvantages. Most importantly, if the operator is distracted when he is shifting one quill and then the other to adjust the backlash, the entire process must be started over because the bearing pre-load will no longer be correct. In addition, the operator must constantly switch his screwdriver back and forth between the different crenellations, which is inconvenient and takes time. The overall process is inefficient, and even an experienced factory worker who does nothing but adjust differentials takes 30 to 60 minutes per differential. A typical mechanic in a repair shop in the field who does not do this regularly is more likely to take several hours.